This study proposes and experimentally demonstrates a novel image rejection microwave photonic mixer structure based on a dual-driven Mach-Zehnder modulator (DDMZM) and stimulated Brillouin scattering (SBS) narrow-band photonic filtering. In this structure, the radio frequency (RF) and local oscillator (LO) signals are input to the RF ports of the DDMZM on the upper and lower arms, respectively. The optical sideband caused by the RF and LO signals satisfies the equivalent phase modulation relation by bias voltage control; hence, the in-band interference intermediate frequency (IF) signals generated by the frequency beating of the RF and LO optical sidebands can be rejected. Furthermore, with the narrow-band photonic filtering characteristic of the SBS loss spectrum, a useful IF signal is generated by converting the equivalent phase modulation to the intensity modulation relation between the useful RF and LO optical sidebands. The experimental results show that the image rejection ratio(IRR) of this mixer can reach 43dB. The IRR performance of the system can be maintained at a 35dB--40dB level in the operating frequency band of the 6--20GHz RF signal and the 0.5--1.5GHz IF signal.